I would suggest that first of all you run a full system scan with your anti virus and then with Malware Bytes. The behavior that you are describing, i.e. you click on one video and it would jump to another video, does appear somewhat strange. Is this behavior only with Firefox or with other software on Windows 10 too? For example do you observe that in a spreadsheet (say excel or Libre Calc or Lotus 123, etc) when you try to click on one cell but it would take you to another cell? To answer your question about restoring your profile, please refer to the document [https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile Recovering important data from an old profile]